Background: New Zealand has one of the highest rates of obesity and obesity-related diseases in the world. Claims have suggested that a low glycaemic index diet will curb cravings to overeat by keeping you feeling fuller for longer. However, there is conflicting data regarding the relationship between GI and satiety.

Objective: To determine the effect on measures of satiety and blood glucose of two test foods with different glycaemic indices but otherwise identical composition within a healthy New Zealand adult population.

Design: Randomised double-blinded crossover control trial. The main contribution of this study is to present novel findings in relation to the ongoing scientific glycaemic index debate through the consistency of altering one variable only in humans over a two day trial.

Methods: Seventy-seven participants were randomised to receive the isomaltulose- and the sucrose-sweetened trifles over two testing days, with two to three weeks in between. Only the glycaemic index differed between trifles so that any differences could only be attributed to the rate of digestion of the sugars. Blood samples were collected at baseline, 60 and 120 minutes and were analysed for blood glucose. Subjective satiety was measured using a fourquestion visual analogue scale questionnaire at baseline, 30, 60, 90, 120 and 150 minutes. Weighed diet records were used to obtain subsequent energy intake for comparison between the trifles.

Results: Blood glucose rose at 60 minutes then declined at 120 minutes, though remained above baseline for both trifles. A statistically significant difference between trifles was observed at 60 minutes following consumption, with a difference of 0.69 mmol/L (95%CI: -1.12, -0.25; p<0.05). Mean satiety AUC did not significantly differ between the isomaltulose- and sucrose-sweetened trifles. There was also no significant difference in subsequent energy intake between the trifles, though there was a tendency for increased energy intake following the consumption of the isomaltulose-sweetened trifle (364kJ, 95%CI: -110, 838; p=0.133).

Conclusion: No significant differences were found between the trifles for satiety or subsequent energy intake. Under our test conditions, the glycaemic response was not related to satiety or subsequent energy intake.